The Southeastern Asians discovered oranges, but it was the Romans who first cultivated them in Europe around the time of Christ. By the 15th century oranges were an expensive, much sought luxury. Columbus planted the first orange seeds in the New World, where they flourished.

Today, the United States is the world's leading orange-producing nation, with the annul yield more than twice that of any other country. Florida, California, Texas and Arizona are the leading producer states, with the greatest single use of their collective product being made into orange juice. The popularity of orange juice, however, is a post-1920 phenomenon.

Until the early 20th century, oranges in America were principally served as dessert. Early 20th-century advances in nutrition and dietetics were responsible for public awareness of the value citrus fruit plays in daily diet. As with so many things, however, there is a direct relationship between the increased popularity of orange juice and the decrease in quality as mass production and processing rise to meet demand. The truth is that no frozen orange-juice concentrate can match juice freshly squeezed.

The following recipes explore the wide variety of uses that can be found for oranges beyond the usual. The first is the creation of Jan Meyer: ORANGE/AVOCADO SALAD MEYER (8 to 10 servings) SAUCE: 1/2 cup salad oil 1/4 cup fresh orange juice 2 tablespoon sugar 2 tablespoons red wine vinegar 2 tablespoons fresh lemon juice 1/2 teaspoon salt 1 tablespoon grated orange rind 1 tablespoon grated lemon rind Pinch poppy seed SALAD: 3 heads Boston lettuce or 2 heads Boston and 1 head Romaine 3 ripe avocados 3 11-ounce cans Mandarin oranges (drained) 3 cucumbers 2 bananas 2 tablespoons chopped green onion (optional)

Combine all of the ingredients for the sauce in a jar of cruet and shake well. The sauce must be prepared at least 4 or 5 hours prior to when it is to be served, and it is best if it is made the night before.

Break the lettuce into a large bowl. Peel and dice the avocados, slice the cucumber and bananas and combine with the oranges and green onion. Pour the sauce over the mixture and toss gently. Makes a find accompaniment to highly spiced entrees or barbecued meats. BREAST OF CHICKEN A L'ORANGE (6 servings) 3 whole chicken breasts, split 6 pats of softened butter 1 small onion, minced 2 carrots grated 2 ribs celery, minced 2 tablespoons grated orange rind Juice of 1 orange 3/4 cup dry white wine 1/2 cup chicken stock or bouillon Salt and pepper to taste 2 tablespoons cornstarch dissolved in 2 tablespoons water Paprika Thinly sliced orange rounds for garnish

Rub each chicken breast with softened butter. Spread the onion, carrot celery and orange rind over the bottom of a shallow baking dish. Place the chicken on top of the vegetables; mix 1/2 cup orange juice and 1/4 cup wine and pour it over the chicken. Bake it 350 degrees for 50 minutes to 1 hour, basting the chicken about every 10 minutes. Remove the chicken to a hot platter and keep warm.

Without pouring off any of the pan juices or softened vegetables, add remaining orange juice, wine and stock, scraping up any bits which have attached themselves to the pan. Pour that mixture through a medium fine wire strainer into a small saucepan, forcing the vegetables through the strainer with the back of a spoon. Bring the mixture to a slow boil over low heat and add salt and pepper to taste; add the cornstarch mixture, stirring until the sauce thickens. Pour the sauce over the chicken and dust with paprika. Garnish the platter with thinly sliced orange rounds. Serve immediately. SWEET ORANGE SAUCE (8 servings) 3 tablespoons sweet butter 1/2 cup sugar 2 1/2 tablespoons cornstarch 2 pinches salt 1 cup fresh orange juice 2 tablespoons fresh lemon juice 1 tablespoon grated orange rind 1 teaspoon grated lemon rind 1 tablespoon orange liqueur

In a small bowl combine the sugar, cornstarch, salt, orange and lemon juice. Melt the butter in a saucepan over moderate heat and add the orange mixture. Cook and stir until the sauce begins to thicken. Add the lemon and orange rind and the liqueur and continue stirring for 2 to 3 more minutes. Serve over hot gingerbread, banana bread, pumpkin or carrot cake, pound cake or over crepes stuffed with mandarin oranges.